arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections

KASAN needs to know whether the allocation happens in an IRQ handler.
This lets us strip everything below the IRQ entry point to reduce the
number of unique stack traces needed to be stored.

Move the definition of __irq_entry to <linux/interrupt.h> so that the
users don't need to pull in <linux/ftrace.h>.  Also introduce the
__softirq_entry macro which is similar to __irq_entry, but puts the
corresponding functions to the .softirqentry.text section.

Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

23 files changed, 51 insertions, 15 deletions

diff --git a/arch/arm/include/asm/exception.h b/arch/arm/include/asm/exception.h
index 5abaf5bbd985f1..bf1991263d2df2 100644
--- a/arch/arm/include/asm/exception.h
+++ b/arch/arm/include/asm/exception.h
@@ -7,7 +7,7 @@
 #ifndef __ASM_ARM_EXCEPTION_H
 #define __ASM_ARM_EXCEPTION_H
 
-#include <linux/ftrace.h>
+#include <linux/interrupt.h>
 
 #define __exception	__attribute__((section(".exception.text")))
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 1fab979daeaf1c..e2c6da096cefa4 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -108,6 +108,7 @@ SECTIONS
 			*(.exception.text)
 			__exception_text_end = .;
 			IRQENTRY_TEXT
+			SOFTIRQENTRY_TEXT
 			TEXT_TEXT
 			SCHED_TEXT
 			LOCK_TEXT
diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index 6cb7e1a6bc02a5..0c2eec490abf65 100644
--- a/arch/arm64/include/asm/exception.h
+++ b/arch/arm64/include/asm/exception.h
@@ -18,7 +18,7 @@
 #ifndef __ASM_EXCEPTION_H
 #define __ASM_EXCEPTION_H
 
-#include <linux/ftrace.h>
+#include <linux/interrupt.h>
 
 #define __exception	__attribute__((section(".exception.text")))
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 37f624df68fad0..5a1939a74ff358 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -103,6 +103,7 @@ SECTIONS
 			*(.exception.text)
 			__exception_text_end = .;
 			IRQENTRY_TEXT
+			SOFTIRQENTRY_TEXT
 			TEXT_TEXT
 			SCHED_TEXT
 			LOCK_TEXT
diff --git a/arch/blackfin/kernel/vmlinux.lds.S b/arch/blackfin/kernel/vmlinux.lds.S
index c9eec84aa25862..d920b959ff3a4b 100644
--- a/arch/blackfin/kernel/vmlinux.lds.S
+++ b/arch/blackfin/kernel/vmlinux.lds.S
@@ -35,6 +35,7 @@ SECTIONS
 #endif
 		LOCK_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		KPROBES_TEXT
 #ifdef CONFIG_ROMKERNEL
 		__sinittext = .;
diff --git a/arch/c6x/kernel/vmlinux.lds.S b/arch/c6x/kernel/vmlinux.lds.S
index 5a6e141d1641bc..50bc10f97bcb4a 100644
--- a/arch/c6x/kernel/vmlinux.lds.S
+++ b/arch/c6x/kernel/vmlinux.lds.S
@@ -72,6 +72,7 @@ SECTIONS
 		SCHED_TEXT
 		LOCK_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		KPROBES_TEXT
 		*(.fixup)
 		*(.gnu.warning)
diff --git a/arch/metag/kernel/vmlinux.lds.S b/arch/metag/kernel/vmlinux.lds.S
index e12055e88bfe5e..150ace92c7ade9 100644
--- a/arch/metag/kernel/vmlinux.lds.S
+++ b/arch/metag/kernel/vmlinux.lds.S
@@ -24,6 +24,7 @@ SECTIONS
 	LOCK_TEXT
 	KPROBES_TEXT
 	IRQENTRY_TEXT
+	SOFTIRQENTRY_TEXT
 	*(.text.*)
 	*(.gnu.warning)
 	}
diff --git a/arch/microblaze/kernel/vmlinux.lds.S b/arch/microblaze/kernel/vmlinux.lds.S
index be9488d697347c..0a47f041055416 100644
--- a/arch/microblaze/kernel/vmlinux.lds.S
+++ b/arch/microblaze/kernel/vmlinux.lds.S
@@ -36,6 +36,7 @@ SECTIONS {
 		LOCK_TEXT
 		KPROBES_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		. = ALIGN (4) ;
 		_etext = . ;
 	}
diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
index 0a93e83cd01479..54d653ee17e1a8 100644
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -58,6 +58,7 @@ SECTIONS
 		LOCK_TEXT
 		KPROBES_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		*(.text.*)
 		*(.fixup)
 		*(.gnu.warning)
diff --git a/arch/nios2/kernel/vmlinux.lds.S b/arch/nios2/kernel/vmlinux.lds.S
index 326fab40a9de0c..e23e8953996771 100644
--- a/arch/nios2/kernel/vmlinux.lds.S
+++ b/arch/nios2/kernel/vmlinux.lds.S
@@ -39,6 +39,7 @@ SECTIONS
 		SCHED_TEXT
 		LOCK_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		KPROBES_TEXT
 	} =0
 	_etext = .;
diff --git a/arch/openrisc/kernel/vmlinux.lds.S b/arch/openrisc/kernel/vmlinux.lds.S
index 2d69a853b742e9..d936de4c07cadd 100644
--- a/arch/openrisc/kernel/vmlinux.lds.S
+++ b/arch/openrisc/kernel/vmlinux.lds.S
@@ -50,6 +50,7 @@ SECTIONS
 	  LOCK_TEXT
 	  KPROBES_TEXT
 	  IRQENTRY_TEXT
+	  SOFTIRQENTRY_TEXT
 	  *(.fixup)
 	  *(.text.__*)
 	  _etext = .;
diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index 308f29081d461b..f3ead0b6ce4615 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -72,6 +72,7 @@ SECTIONS
 		LOCK_TEXT
 		KPROBES_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		*(.text.do_softirq)
 		*(.text.sys_exit)
 		*(.text.do_sigaltstack)
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index d41fd0af89807c..2dd91f79de05a7 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -55,6 +55,7 @@ SECTIONS
 		LOCK_TEXT
 		KPROBES_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 
 #ifdef CONFIG_PPC32
 		*(.got1)
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index 445657fe658cc6..0f41a828637850 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -28,6 +28,7 @@ SECTIONS
 		LOCK_TEXT
 		KPROBES_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		*(.fixup)
 		*(.gnu.warning)
 	} :text = 0x0700
diff --git a/arch/sh/kernel/vmlinux.lds.S b/arch/sh/kernel/vmlinux.lds.S
index db88cbf9eafdc8..235a4101999fe5 100644
--- a/arch/sh/kernel/vmlinux.lds.S
+++ b/arch/sh/kernel/vmlinux.lds.S
@@ -39,6 +39,7 @@ SECTIONS
 		LOCK_TEXT
 		KPROBES_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		*(.fixup)
 		*(.gnu.warning)
 		_etext = .;		/* End of text section */
diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S
index f1a2f688b28a31..aadd321aa05db9 100644
--- a/arch/sparc/kernel/vmlinux.lds.S
+++ b/arch/sparc/kernel/vmlinux.lds.S
@@ -48,6 +48,7 @@ SECTIONS
 		LOCK_TEXT
 		KPROBES_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		*(.gnu.warning)
 	} = 0
 	_etext = .;
diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S
index 0e059a0101ea30..378f5d8d1ec8aa 100644
--- a/arch/tile/kernel/vmlinux.lds.S
+++ b/arch/tile/kernel/vmlinux.lds.S
@@ -45,6 +45,7 @@ SECTIONS
     LOCK_TEXT
     KPROBES_TEXT
     IRQENTRY_TEXT
+    SOFTIRQENTRY_TEXT
     __fix_text_end = .;   /* tile-cpack won't rearrange before this */
     ALIGN_FUNCTION();
     *(.hottext*)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index d239639e0c1dd4..4c941f88d405fb 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -101,6 +101,7 @@ SECTIONS
 		KPROBES_TEXT
 		ENTRY_TEXT
 		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
 		*(.fixup)
 		*(.gnu.warning)
 		/* End of text section */
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 8f5a12ab2f2b9a..339125bb4d2cf9 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -456,7 +456,7 @@
 		*(.entry.text)						\
 		VMLINUX_SYMBOL(__entry_text_end) = .;
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 #define IRQENTRY_TEXT							\
 		ALIGN_FUNCTION();					\
 		VMLINUX_SYMBOL(__irqentry_text_start) = .;		\
@@ -466,6 +466,16 @@
 #define IRQENTRY_TEXT
 #endif
 
+#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
+#define SOFTIRQENTRY_TEXT						\
+		ALIGN_FUNCTION();					\
+		VMLINUX_SYMBOL(__softirqentry_text_start) = .;		\
+		*(.softirqentry.text)					\
+		VMLINUX_SYMBOL(__softirqentry_text_end) = .;
+#else
+#define SOFTIRQENTRY_TEXT
+#endif
+
 /* Section used for early init (in .S files) */
 #define HEAD_TEXT  *(.head.text)
 
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 6d9df3f7e334c3..dea12a6e413bcf 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -811,16 +811,6 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
  */
 #define __notrace_funcgraph		notrace
 
-/*
- * We want to which function is an entrypoint of a hardirq.
- * That will help us to put a signal on output.
- */
-#define __irq_entry		 __attribute__((__section__(".irqentry.text")))
-
-/* Limits of hardirq entrypoints */
-extern char __irqentry_text_start[];
-extern char __irqentry_text_end[];
-
 #define FTRACE_NOTRACE_DEPTH 65536
 #define FTRACE_RETFUNC_DEPTH 50
 #define FTRACE_RETSTACK_ALLOC_SIZE 32
@@ -857,7 +847,6 @@ static inline void unpause_graph_tracing(void)
 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 
 #define __notrace_funcgraph
-#define __irq_entry
 #define INIT_FTRACE_GRAPH
 
 static inline void ftrace_graph_init_task(struct task_struct *t) { }
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 358076eda364ec..9fcabeb07787b7 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -683,4 +683,24 @@ extern int early_irq_init(void);
 extern int arch_probe_nr_irqs(void);
 extern int arch_early_irq_init(void);
 
+#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
+/*
+ * We want to know which function is an entrypoint of a hardirq or a softirq.
+ */
+#define __irq_entry		 __attribute__((__section__(".irqentry.text")))
+#define __softirq_entry  \
+	__attribute__((__section__(".softirqentry.text")))
+
+/* Limits of hardirq entrypoints */
+extern char __irqentry_text_start[];
+extern char __irqentry_text_end[];
+/* Limits of softirq entrypoints */
+extern char __softirqentry_text_start[];
+extern char __softirqentry_text_end[];
+
+#else
+#define __irq_entry
+#define __softirq_entry
+#endif
+
 #endif
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 8aae49dd7da862..17caf4b63342d7 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -227,7 +227,7 @@ static inline bool lockdep_softirq_start(void) { return false; }
 static inline void lockdep_softirq_end(bool in_hardirq) { }
 #endif
 
-asmlinkage __visible void __do_softirq(void)
+asmlinkage __visible void __softirq_entry __do_softirq(void)
 {
 	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
 	unsigned long old_flags = current->flags;
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 91d6a63a2ea760..3a0244ff7ea8df 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -8,6 +8,7 @@
  */
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
+#include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/fs.h>